How much climate change can be avoided by mitigation?

Avoiding the most serious climate change impacts will require informed policy decisions. This in turn will require information regarding the reduction of greenhouse gas emissions required to stabilize climate in a state not too much warmer than today. A new low emission scenario is simulated in a global climate model to show how some of the impacts from climate change can be averted through mitigation. Compared to a non‐intervention reference scenario, emission reductions of about 70% by 2100 are required to prevent roughly half the change in temperature and precipitation that would otherwise occur. By 2100, the resulting stabilized global climate would ensure preservation of considerable Arctic sea ice and permafrost areas. Future heat waves would be 55% less intense, and sea level rise from thermal expansion would be about 57% lower than if a non‐mitigation scenario was followed.